Fluoxetine-induced SIADH: a geriatric occurrence?

Area of Science:

• Geriatric Medicine
• Clinical Pharmacology
• Endocrinology

Background:

• Major depression is a common diagnosis in the elderly population.
• Selective serotonin reuptake inhibitors (SSRIs) like fluoxetine are frequently prescribed for depression.
• Electrolyte imbalances can present with non-specific symptoms in older adults.

Observation:

• An 83-year-old woman was treated with fluoxetine for major depression.
• Within six days, she developed delirium and weakness, requiring hospitalization.
• Initial assessment revealed severe hyponatremia.

Findings:

• The patient's hyponatremia was diagnosed as secondary to fluoxetine-induced syndrome of inappropriate antidiuretic hormone secretion (SIADH).
• Discontinuation of fluoxetine led to a complete recovery of the patient's condition.
• This case highlights a rare but serious adverse drug reaction to fluoxetine.

Implications:

• Clinicians should consider SIADH as a potential cause of hyponatremia in elderly patients initiating fluoxetine.
• Early recognition and discontinuation of the offending agent are crucial for managing drug-induced SIADH.
• This case underscores the importance of careful medication monitoring in geriatric patients to prevent adverse drug events.